Re: Contour Machining, was Optimizing cutting paths, was Traveling Salesman

Thanks for the info Fred, your description of the treatment of
islands is good.

When I've tried to produce a contoured pocket from a series of offset
toolpaths, the problem arose as to what to do when the toolpath meets
up with or overlaps itself. Seems to need a way of automaticaly
detecting and removing the redundant portions of the toolpath.

Rab

> The contouring method of pocketing is actually quite easy as it is

a

> series of offsets from the outer contour(a closed planar shape),
> something that most Cam software can do fairly well. It gets a bit
> complicated with islands, but you just treat the island as a
> peninsula with a very small isthmus, and multiple islands as a
> peninsula with several areas(nearly islands) connected by very

small

> isthmi.
>
> The cuts actually originate in the center of the part and finish at
> the side walls of the pocket, just reversed from how they are
> developed.
>
> Horizontal or zig-zag pocketing is the other major 2D area clearing
> method. Like contour pockets, it is a 2D process. Both will

result

> in tool pickups if blind canyons are created in the contour

designs.

> Some people use hatching as zig-zag pocketing, if their CAD system
> will all them to be interpreted as lines.
>
> Best Regards,
>
> Fred Smith
> IMService